Field of the Invention
The present invention relates to methods and devices for obtaining variable optical attenuation of a waive guide, and in particular to such methods and apparatus which cause radiation losses by selected curving of the waveguide.
Optical attenuation means making use of so-called fiber offset losses are known wherein two glass fibers are arranged with their respective end faces offset relative to one another. Adjustment of attenuation means of this type requires considerable technical outlay.
Other types of optical attenuation means are known which operate on the principal of absorption attenuation in imaging optical systems. Such attenuation means also typically require considerable technical outlay.
Attenuation means of the type described above all require as a condition for operation an enlargement of the fiber distance or line, which involves unavoidable additional signal losses.